وَمَنْ بَاعَ عَبْدًا عَلَى أَنَّهُ خَبَّازٌ أَوْ كَاتِبٌ فَكَانَ بِخِلَافِ ذَلِكَ فَالْمُشْتَرِي بِالْخِيَارِ: إِنْ شَاءَ أَخَذَهُ بِجَمِيعِ الثَّمَنِ وَإِنْ شَاءَ تَرَكَ
Translation: If a person was historically sold as an enslaved worker described as a baker or scribe, but lacked that promised skill, the purchaser could accept at the full agreed price or rescind.
This is a historical legal example from an earlier institution of enslavement; it does not validate present-day trafficking or sale of people.
The doctrinal point is failure of an expressly promised attribute. The remedy stated here is a choice between accepting at the full agreed price and rescinding, not an automatic discount.